entity-framework - CTP5 与 4.1 EF 版的多对多关系

此代码不起作用。怎么了？ OnModelCreating 不会影响任何结果？因为我在我的数据库中看不到“ProductCategories”表。

    public class GoldContext : DbContext
    {
        public virtual DbSet<Prouct> Products { get; set; }
        public virtual DbSet<Category> Categories { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        //HACK:4.1 modelBuilder.Conventions.Add(new DecimalPrecisionAttributeConvention());
        modelBuilder.Entity<Product>()
            .HasMany<Category>(m => m.Categories)
            .WithMany().Map(m =>
                m.MapLeftKey("ProductId")
                .MapRightKey("CategoryId")
                .ToTable("ProductCategories"));
        base.OnModelCreating(modelBuilder);
    }
}

//product and category classes look like this.

    public class Product
    {
        [Key]
        public int Id { get; set; }

        public virtual string Name { get; set; }

        public virtual ICollection<Category> Categories { get; set; }
    }

    public class Category
    {
        [Key]
        public int Id { get; set; }

        public virtual string Name { get; set; }

        public virtual ICollection<Product> Products { get; set; }
    }

提前致谢。

最佳答案

这是我在控制台应用程序中尝试过的并且按预期工作:

namespace Q7122388
{
    #region Imports

    using System;
    using System.Collections.Generic;
    using System.ComponentModel.DataAnnotations;
    using System.Data.Entity;
    using System.Linq;

    #endregion

    public class Product
    {
        [Key]
        public int Id { get; set; }

        public virtual string Name { get; set; }

        public virtual ICollection<Category> Categories { get; set; }
    }

    public class Category
    {
        [Key]
        public int Id { get; set; }

        public virtual string Name { get; set; }

        public virtual ICollection<Product> Products { get; set; }
    }

    public class DatabaseContext : DbContext
    {
        public virtual DbSet<Product> Products { get; set; }
        public virtual DbSet<Category> Categories { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Product>()
                .HasMany<Category>(m => m.Categories)
                .WithMany().Map(m =>
                    m.MapLeftKey("ProductId")
                    .MapRightKey("CategoryId")
                    .ToTable("ProductCategories"));
            base.OnModelCreating(modelBuilder);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Database.SetInitializer(new DropCreateDatabaseAlways<DatabaseContext>());
            using (var context = new DatabaseContext())
                context.Database.Initialize(true);
        }
    }
}

关于entity-framework - CTP5 与 4.1 EF 版的多对多关系，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/7122388/